A radio modem is a device enabling data coming from equipment such as a personal computer (PC) to be transmitted by radio.
An example of an application for the present invention consists in using a mobile radio communications system such as the GSM system in particular (xe2x80x9cGlobal System for Mobile communicationsxe2x80x9d) to transmit data from equipment such as a portable computer, in particular.
In a system such as the GSM system, for example, it is known to provide mobile terminals with memory card readers, also known in the GSM system as SIM cards (for xe2x80x9cSubscriber Identity Modulexe2x80x9d), thus making it possible to identify the users of such mobile terminals in order to control their access to the services provided by the system.
In the present specification, the term xe2x80x9cmemory card readerxe2x80x9d is used to mean a device that performs both the mechanical and the electrical functions that are necessary for holding the card and for reading the information stored in the card.
It is thus known for GSM portable telephones to be fitted with SIM card readers.
Nevertheless, it is not presently known to provide a GSM radio modem for fitting to equipment such as a portable computer, in particular, with an SIM card reader. Such GSM radio modems are themselves generally made in the form of a card that is designed to be inserted in a slot provided in the equipment (with such a card being referred to herein as an xe2x80x9cequipmentxe2x80x9d card in order to distinguish it from the xe2x80x9cmemoryxe2x80x9d card which is of considerably smaller thickness), and in addition it is not obvious how to provide a memory card reader in such an equipment card.
By way of example of an equipment card, mention is made of PCMCIA type cards (for xe2x80x9cPersonal Computer Memory Card International Associationxe2x80x9d), of length and width similar to those of a credit card type memory card, and of thickness that may either be 5 mm or 10.5 mm, depending on whether the card is a so-called PCMCIA type II card or a PCMCIA type III card.
Thus, it is known to make a radio modem in the form of a type III PCMCIA card, and to provide in the equipment which is to receive the modem a slot having dimensions and in particular thickness adapted to receiving that type of card.
Also, when the components corresponding to the radio portion proper of the modem function (as opposed to its portions for frequency conversion and for baseband processing) are too bulky to be capable of being housed in the modem card, it is known to house them in a separate module that is in the form of a projection from the card that sticks out from the slot when the modem card is in its inserted position.
A particular object of the present invention is to provide a radio modem implemented using the concept of an equipment card, and in particular a card of the PCMCIA type, that is capable of being provided with a reader for a memory card, such as an SIM card, in particular.
The present invention thus provides a radio modem for fitting to equipment such as a portable computer, in particular, the modem being deigned to be inserted in a slot provided in the equipment, and the modem essentially comprising two elements which are disposed relative to each other and which are fitted so as to form a memory card reader, and wherein, for the slot having dimensions adapted for receiving a modem in the form of an xe2x80x9cequipmentxe2x80x9d card of determined thickness, each of the two elements is implemented by means of an equipment card of thickness that is smaller than the determined thickness.
According to another characteristic, the determined thickness is the thickness of an xe2x80x9cequipmentxe2x80x9d card of PCMCIA type III, and each of the elements is implemented by means of an xe2x80x9cequipmentxe2x80x9d card of PCMCIA type II.
Thus, the present invention enables better use to be made of existing card and slot formats by providing the additional function of a memory card reader, while nevertheless still retaining existing formats.
According to another embodiment of the present invention, only one of the PCMCIA type II cards is connected to the equipment, and any connection required between the two cards for the purpose of performing the modem function takes place via another element referred to as a connector module.
The advantage of the invention is thus further increased because it is not necessary to modify the connection means that need to be provided on the equipment in order to enable it to be fitted with a modem of the invention, as compared with the situation of a prior art modem implemented by means of a type III PCMCIA card (it being understood that the connector means provided on a PCMCIA card are identical and are located at the same position on the card, regardless of whether the card is of type II or type III).
According to another embodiment, each of the PCMCIA type II cards is provided with a connector placed along its edge, and the two PCMCIA type II cards are mounted head to tail so that the connector of the card which is not connected to said equipment can be used to connect it to the connection module.
This serves to provide mechanical strength to the assembly, without any need to provide special means for this purpose.
According to another embodiment, the connection module is constituted by a module that is in the form of a projection on one of the cards that sticks out from slot when module is in the inserted state, and that is designed to contain circuits that are too bulky to be contained in the card.
The invention thus makes it possible yet again to take advantage of existing elements to provide new functions at a lower cost.